Lubrication system



Feb. 16, 1960 R. D. wEATHl-:RBEE 2,925,215

LUBRICATION SYSTEM Filed June 20, 1957 MM m HTTOR'VV United Seite yPaffnf IO.

to United Aircraft Corporation, East Hartford, Conn., a corporation ofDelaware Application June 20, 1957, Serial No. 666,848 `6 Claims. (Cl.230-116) This invention relates to a compressor-turbine` unit adapted tocompress and cool air and more particularly to the bearing lubricationand cooling system to be used therewith.

It is an object of this invention to teacha lubrication system for usewith a high speed turbine and compressor unit which utilizes an impellerto provide a lubricantmist and to circulate that mist througha circuitalpath `to lubricate and cool the unit bearings.

It is a further object of this invention to teachia lubrication systernfoi use `with `a lcompressor-turbine unit `in which compressor provided`air is utilized to seal the lubricant mist within its intended chamber.

It is a furtheryobject of this invention to Vteach a lubri cating andcooling system for ahigh speed compressorfturbine unit inwhich-lubricantis raised from a sump and directed to animpeller inlet as a function ofcompressor generated pressure. p A

It isa furtherfobject of this invention to provide a lubricating andcooling system for a compressor-turbine unit by bleeding compressor air,forming a lubricant mist c'ation and cooling is eventually directed to asepara-tor where the lubricant and air are separated and both dischargedfor further use. i

It is a further object of this invention to provide a lubricating andcooling system for a `compressor-turbine unit by bleeding compressorair,formnig a lubricant mist by mixing the bleed air with lubricant andcirculating the mist over the unit bearings.

It is still a further object of this invention to provide a lubricationsystem fora high speed compressorturbine unit which is completelyenclosed and pressurized so that the compressed air, the compressedair-lubricant mist and the lubricant are retained within the system forfurther utilization after they have accomplished .their lubri coolingfunctions the compressor-turbine` cating and unit.

It is still a further object of thisinvention to provide a high speedcompressor-turbine unit in which compressed air is introduced to andfurther compressed by the compressor and then passed throughthe turbinefor cooling such that the compressor provides a load for the turbine,which `unit-has a pressure regulated lubricant mist lubrication andcooling system.

Other objects andadvantagesiwill be apparent from the specification andclaims, `and from the accompanying drawing which illustrates anembodiment of the invention. A

In the drawing: .y

Fig. 1 is a cross sectional view of the compressor-turbine unit taughtherein; and p Fig. 2 is an external view of the compressor-turbine unittaught herein showing 4the external lubricant-mist, lubricant and aircarrying lines and with portions broken away to illustrate interiorconfigurations.

While it will be obvious to those skilled in the art that m w.. e

i perform -such functions `as 2,925,215 Patented Feb.. 16, 1960 ingsystem taught herein have enumerable applications, for purposes ofdescription and to show a complete embodiment, `both the drawingsanddescription will be given with respect to anauxiliarycompressor-turbine unit to providec'ool, compressed air to a modernaircraft to passenger cabin cooling and pressurization.

Referring to Fig. l it Vwill be noted that compressorturbine unit 10comprises compressor 12 and turbine 14. CompressorflZ and turbine 14 aremounted back-to-back for rotation on shaft 16. Shaft 16 is rotatablysupported by at least one bearing suchas 18 and 20 and carries impeller22 for rotation therewith.,` Impeller 22 is providedwithcircumferentially spacedl impelling blades or fins 24. Housing 26supports bearings 18 and 20 and contains lubricatingcavity orchamber 28which envelops bearings 18 and 20 and-impeller 22. Plates 30 and 32,

which may be a part of housing 26, join housing 26 in sealingrelationwith shaft 16 to form cavity 28. Seals 34 and 36,1which may beof the labyrinth type are `.rnountedfor rotation on shaft 16 and arelocated in where it wllbe further compressed by auxiliary com? pressor12 and then discharged to'compressor discharge 46 from whence it will beaccumulated in manifold 48 and then ducted through line 49 to duct 5l)for admission to inlet 52 of turbine 14. The air may be cooled bothbefore and after leaving compressor 1.2 and an insert 53 may be placedon shaft 16 to prevent the ow of heat from compressor 12 to housing 26through shaft 16. Insert 53 may be made of Alundum. The compressed airis cooled considerably in passing through turbine 14 and the cooledturbine discharge compressed air is passed through passage 54 Where itperforms a heat exchange and scrubbing action on surface 56 of housing26 to extract heat therefrom and, therefore, cool the lubricant mistbeing passed through cavity 28. After leaving duct 54, the turbinedischarge compressed air is then passed through duct 58 for admission tothe aircraft cabin as cool compressed air for pressurization and airconditioning purposes. It is an important feature of this invention thatthe air passing through duct 58 be free of lubricant for passengercomfort when this air is used for passenger. cabin pressurization and toprevent detrimental lubricant deposit on moving parts when `this air isused for other purposes. t

Since the lubrication and cooling system, now to be described, ispressure actuated, reference letters have been placedin Fig. l todesignate pressure areas in the order of decreasing pressure. Thehighest pressure area in the system exists at area A and the pressure inarea B is somewhat less since in passing from area A to area B, thecompressor discharge air A must be bled through pressure area B willeventually be utilized and recovered. The next lowest pressurized areais area C, which is fed compressor scavenge air through line 66 and thenthrough line 68 from whence it is passed between labyrinthseal It willbe noted that, asl described hereinafter, compressor scavenge air from.

36 and plate -32 into the "chamber of pressure area C. The nextpressurized chamber is designated as D, which is also cavity 28. As willbe shown later, cavity 28 is in communication with the Vturbinedischarged area due. 'tothe connections between area 11), t-"anktype'sump 70,

and air-lubricant inist collector 'and separatorcan l72. The nextpressurized area "is area E, in snp v70, which will be somewhat .lessthan thefpre'ssure in area D due toline losses. The fne'xt pressurizedarea is area' `.E, Whichis the inlet side of imt'aeller '22 and which'will obviously be less than the dischargeside of jirin'elle'r 22, orlarea D. The last pressurizedarea -`is area G, which will be shown later-to be iin communication with and, therefore, substantially the'discharge pressure from tur'- bine 14.

With respect Vto fthe lubrication system, lubricant, which may be o il,is conducted from *"s'ur'n'p 70, which i'sjlocated at the bottom vofVhousing 26 lfor i'gravity drain purposes, through line 74, into'annular-chanibe`r`76an' l t'lrenthjrough restricted orifice or jet 78which opens into `the Vinlet "f impellers 22. While 'pump 80 may besedjto purrip lubricant throught-line y'74 'to lubricant ljet 78, suc`hmay not be found lt'oabe necessary due i'to Vthe 'fact .that thepressure at jet 78,1is the `inlet pressure'to irripellerZZfwhile thepressure :acting on the lubricantin fsump`70 i's 'sub'-V stantially'impeller dischargelpressu're s otha't thepres r'e diiferential acrossi'rn'peller `22will 'cause thelubr'icaiit t'o rise through line 74 andto be'dircte'd against lijrrip'elle'r 22 throughzjet .78at allhighfspeedconditions- Because pressor turbine lunit 1'0 lmay be requiredto jc'nper'at'e.`

a wide range of lc'o'nditi'orfs, t-he lpump may be nec sary to assure anadequate ow of oil. Duc to the comp tions Yof :gearing to `a high 'speed'shafft, lit nay be sidered `preferable to Idrive pump/ 180 byVan'zuiriliary bine 82 .which I'is -fe'd air from 'the 'inlet of"turbine "Iii through line 84.

Thelubricant jt vi/h'it'll 'passes 'ftlirgi'h Vitiii'l'e -pais'- sag'e78 `-is directed -t`o -irnpinge against 'the whirling blades orns=24ofimpeller 22 and flung cejntr'ifugally as alibricant mist :and lpurnpedby impell'er 'action through chamber 38 of cavity 28, W'hcreit is'cooledby'zthe cooling'eifect of turbine discharge Iair scrubbingagainst surface 5`6 of housing :26 and thence through bearnrg "20,lubricating and cooling same, 'and vthence'through`-bearirg 1'8,-hibricatin'g Tand cooling same, `forfrturn to "impelle :22. forVfurther circulation through this circuitl path. The lubricant .whichseparates en: ef the :lubricant mist will 'be returned .tosurnp 7i)through "line 8'6.

Compressoriscaven'geair from area "B :is ipassed between plate 30ofho'using'lZ and labyrin'thfse'al 34 intocavity'ZS simultaneously "withsuch v'compressed or scaven'ge air which, "as :previously described,V)grasses y'through lines K6 and 68 for'entry intocavity Z'S'be'tWeenplate'32 'of'hosingv26 `andllabyrinth seal 36. Pressure 'build :up incavity 2S'is prevented 'by-the fact thatchamber 28 isin cin- '55 muniftionfwith fsum'p Q70 andsepara'to'r 72. This coinpress )r scavenge 'airenters-cavity 2,8 frorr'ib'oth directions and vserves the lfun'ction ofsealing "the llubricating inist within chamber 28 by preventing itfrom'seeping'ithrouggh seals a'nd 36. 'A vent-line '88, preferably with.relief valve`90 therein, connects compressor'scavenge air charnber Bwith 'turbi'n'e discharge v'c,ih`ai r 1ber '92, which will hereinafterbe described 'to be lin coin rnu'nicat'ion with sump 7i) throughcollector can 72, lsuch that it is substantially at pressure "D, inchamber 28. Vent r88 and ing air will disrupt the desired circulatory owof lubri- 4cant mist through the bearings. Excessive Vvscavenging airflow will reduce effectiveness fof the separator can 72.

The lubricant mist'would be formed and circulated in cavity or chamber28 without the assistance of scavenge air but the scavenge air isnecessary for the sealing function described above. The llow of scavengeair in cavity 28 joins the mist in the'lubricant flow path both incavity 28 and inline 86 but 'is regulated to be sufficiently smallsuchthat this is not'harmful 'l1eatwise. The scavenge air, afterpassingthrough cavity 28 and nline T86 into sump cavity will then .bepassed'due 'to a positive ow caused by pressure diierentals and G` eitherthrough line `94 or 96 to collector "or separator `can72.

Two such lines, 94 .and :96 are Achosen and placed at diagonallyopposite top corners of sump cavity 70 such that an oil mist lineconnection isavailable between sump cavity 70 and collector can 72irresriective of aircraft attitud'ejwithin certain limits, Collector 'orlseparator 72 is located at the top 'of housing 2 6 :for grvit'yid'rainpurposes -:and to give makirnum attitude ekio'ili't'y, For stationaryinstallations, the double line system `will (it be necessary since theselines may 'be Vchosen to b'e of sufficient size that lubri cantrnistvthrug'h "a given line-to the colle or'can 7'2'at time-that the separatedlubric pt is flowing y.do n ward as filmow on the inside surface of`th"e`sj a1fr`ie "l, e in return fromjcollctor can 72 to sump and ibric't-fr en from `reen ispssd through line 8 toconnection `100 v'which.enters turbine discharge fduc't5`. 'v

It is to be understood that the invention is not lirriit'ed to thespeciflc'embodiment herein 1l strateland de scribed, but may beusedi'nother way'switliout departure from its spirit as denedbythefollowiiigfclinis. Y

Iclairn:V ,Y y 1. ln a turbine-compressor 'air compressing 'and coolirigguriit rnounted on a 'shaft `rotatably supporteil fat relief valve'9i)determine `the pressurefdifferencebetween pressures B 'and D,whichfissubstztia'lly `the .pressure drop across impeller 22,v and,ther'efo`r`e, governs the rate of ilow ofcompressorscavnge air intocavit')I l28.

is-"an-important function 'since the compressor discharge air need flowin suicient Vquantity/ to seabthelubricant mist chamber 28; yjetfiftherate of scavenge airiliwvfirlto cavity 2 8 becomes 'too large, thelubricant Vcooling effect VwillV be flost 'due to thefhigh emperatur'eVof the c oin-Y pressoriscaveng'e ain "also, "excessive 'Hows o'f'scavengjleastbriebearing, "abearing lubricating and c sure, `alubricant sump connected `withf tern comprising 'a 'housinghaying :acavity env bearing-and engaging said shaft inV sealing relation at twospaced seal areas ono'pposite sides ffs'aidbe n g, an

Ewith'sid'fshal"rne'ans to direct "a `jet lofIibric'ant agin st saidimpeller so that a lubricant mist is formedandfcirculated 'within saidcavity 'for bearing lubricating and cooling purposes.

Tn Yaturbinecoirprsssor'air'compressingand*cooling unit rnoiintedn a.shaft rotatably rsupported `hyat Fleast one 'bear'in'g, abearinglubricatingand cooling :system comprising a housing having Yafcayity enveloping"lsaid bearing and engagingsaid shafttinfsealingrelation atit`wo 'spaced seal areas :on oppositefsides fofsaidbeaig, "an

impeller having anlinletand anoutlet nd'located irl-:said cavity andmounted for rotation with said shaft so that cavity pressure issubstantially impeller" ischarge `preshaving a lubricant outlet, nozzle'sloca a jacent said irripellerinlet 'andconnected to tlielubricantoutlet of salu "sinripg'sfo that va 'jet fl-Br is directed 'against saidAiinpeller `at 'the nripeller f iltrin .response to Vfithepiesf YcavitifandA nozzle means yso 'that a lubricant mist Vis formed ping iand circulated within said cavity for bearing lubricating and coolingpurposes.

3. An air compression and cooling system comprising a compressor havingan inlet and a discharge side, a turbine having an inlet and a dischargeside, a rotatable shaft joining and spacing said compressor `andturbine, duct means joining said compressor discharge side with saidturbine inlet side, spaced bearings supporting said shaft for rotation,means to support said bearings, an enclosed lubricating system forlubricating and cooling said bearings comprising an impeller mounted forrotation with said shaft, a lubricating cavity enveloping said bearingsand impeller and defining a single circuital path through said bearingsand impeller, spaced seals engaging said shaft and housing to seal saidlubricating cavity, a lubricant sump communicating with said cavity,means to introduce a jet of lubricant against said impeller in responseto the pressure diierence across said impeller.

4. An enclosed air compressing and cooling unit mounted on a shaftrotatably supported by at least one bearing comprisinga compressor and aturbine each having an inlet and a discharge side, means to duct airfrom said compressor to said turbine, a bearing lubricating and coolingsystem comprising a housing having a cavity enveloping said bearing andengaging said shaft in sealing relation at two spaced seal areas onopposite sides of said bearing, an impeller located in said cavity andmounted for rotation with said shaft, a lubricant sump, compressordischarge air driven means to direct a jet of lubricant from said sumpagainst said impeller so that a lubricant mist is formed and circulatedwithin said cavity for bearing lubricating and cooling purposes, meansto separate the lubricant and air from said lubricant mist after saidlubricant mist has circulated through said cavity, means to return saidlubricant so separated tosaid sump, means to return said air soseparated to said turbine outlet, and means to direct compressor airinto said cavity through both of said seal areas to seal said lubricantin said cavity.

5. An air compression and cooling system comprising a compressor havingan inlet and a discharge side, a turbine having an inlet and a dischargeside, a rotatable vshaft joining and spacing said compressor andturbine,

duct means joining said compressor discharge side with said turbineinlet side, spaced bearings supporting said shaft for rotation, means tosupport said bearings, an enclosed lubricaitng system for lubricatingand cooling said bearings comprising an impeller mounted for rotationwith said shaft, a lubricating cavity enveloping said bearings andimpeller and defining a single circuital path through said bearings andimpeller, spaced seals engaging said shaft and housing to seal saidlubricating cavity, -a lubricant sump communicating with said cavity,means to introduce a jet of lubricant against said impeller in responseto the pressure difference across said impeller, means to passcompressor discharge air through each of said seals and into saidlubricating cavity to retain said lubricant in said cavity and to form amist with said lubricant due to impeller action to pass through saidpath to lubricate and cool said bearing, means to separate the lubricantfrom the compressed air of said mist, means to return the lubricant soseparated to said sump, and means to return said compressed air soseparated to said turbine.

6. An air compression and cooling system contained within a housingcomprising a compressor having an inlet and a discharge side, a turbinehaving an inlet and a discharge side, a rotatable shaft joining andspacing said compressor and turbine such that said turbine andcompressor are back-to-back on said shaft, duct means joining saidcompressor discharge side with said turbine inlet side, means to passair through said compressor and turbine, at least one bearing supportingsaid shaft for rotation, an impeller having an inlet and an outletmounted for rotation with said shaft, said housing supporting saidbearing and having a lubricating cavity enveloping said bearing andimpeller and dening a circuital path through said bearing and impeller,seals engaging said shaft one on each side of said bearing land impellerto seal between said shaft and housing lubricating cavity, a tank typeoil sump located at the bottom of said housing, means to turbulentlyintroduce lubricant to said impeller inlet from said sump as a functionof impeller pressure drop so that said lubricant is hurled outwardly asa mist and is circulated through said cavity to lubricate and cool saidbearing by impeller action, means to regulate said impeller pressuredrop, separate turbine inlet air driven means to introduce lubricant tosaid impeller unit, means to pass compressor discharge air through eachof said seals and into said lubricating cavity to retain said lubricantin said cavity and join said circulating mist, a lubricant-air separatorlocated at the top of said housing, a first line joining said cavity tosaid sump and second and third lines connecting diagonally opposed topcorners of said sump to said separator, a fourth line connecting saidturbine inlet air driven means to said separator and a fifth lineconnecting said separator to said turbine discharge so that lubricantmay be gravity drained to said sump from said lubricating cavity and sothat lubricant mist may be passed by pressure differential from saidcavity to said sump through said rst line and from said sump to saidseparator through either said second or third line and so that turbineinlet air may be conducted from said separate drive means to saidseparator by pressure differential and further so that the lubricantseparated from said mist in said separator may be gravity drained tosaid sump through either said second or third line and so that said airseparated from said mist in said separator may be conducted to saidturbine discharge through said fth line by pressure differential, meansto conduct air from said turbine discharge in heat exchanger relation tosaid cavity to cool said mist, and means to prevent heat iiow from saidcompressor to said housing through said shaft.

References Cited in the file of this patent UNITED STATES PATENTS2,492,672 Wood Dec. 27, 1949 2,646,210 Kehlmann et al July 21, 19532,709,567 Wood May 31, 1955 2,775,400 Cox Dec. 25, 1956

